Revert "Correct dwarf unwind information in function epilogue for X86"
This reverts r317100 as it introduced sanitizer-x86_64-linux-autoconf
buildbot failure (build #15606).
llvm-svn: 317136
diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index f7c46ac..40cb0c0 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -296,11 +296,6 @@
return HashMachineInstr(*I);
}
-// Whether MI should be counted as an instruction when calculating common tail.
-static bool countsAsInstruction(const MachineInstr &MI) {
- return !(MI.isDebugValue() || MI.isCFIInstruction());
-}
-
/// ComputeCommonTailLength - Given two machine basic blocks, compute the number
/// of instructions they actually have in common together at their end. Return
/// iterators for the first shared instruction in each block.
@@ -315,9 +310,9 @@
while (I1 != MBB1->begin() && I2 != MBB2->begin()) {
--I1; --I2;
// Skip debugging pseudos; necessary to avoid changing the code.
- while (!countsAsInstruction(*I1)) {
+ while (I1->isDebugValue()) {
if (I1==MBB1->begin()) {
- while (!countsAsInstruction(*I2)) {
+ while (I2->isDebugValue()) {
if (I2==MBB2->begin())
// I1==DBG at begin; I2==DBG at begin
return TailLen;
@@ -330,7 +325,7 @@
--I1;
}
// I1==first (untested) non-DBG preceding known match
- while (!countsAsInstruction(*I2)) {
+ while (I2->isDebugValue()) {
if (I2==MBB2->begin()) {
++I1;
// I1==non-DBG, or first of DBGs not at begin; I2==DBG at begin
@@ -373,35 +368,6 @@
}
++I1;
}
-
- // Ensure that I1 and I2 do not point to a CFI_INSTRUCTION. This can happen if
- // I1 and I2 are non-identical when compared and then one or both of them ends
- // up pointing to a CFI instruction after being incremented. For example:
- /*
- BB1:
- ...
- INSTRUCTION_A
- ADD32ri8 <- last common instruction
- ...
- BB2:
- ...
- INSTRUCTION_B
- CFI_INSTRUCTION
- ADD32ri8 <- last common instruction
- ...
- */
- // When INSTRUCTION_A and INSTRUCTION_B are compared as not equal, after
- // incrementing the iterators, I1 will point to ADD, however I2 will point to
- // the CFI instruction. Later on, this leads to BB2 being 'hacked off' at the
- // wrong place (in ReplaceTailWithBranchTo()) which results in losing this CFI
- // instruction.
- while (I1 != MBB1->end() && I1->isCFIInstruction()) {
- ++I1;
- }
-
- while (I2 != MBB2->end() && I2->isCFIInstruction()) {
- ++I2;
- }
return TailLen;
}
@@ -488,7 +454,7 @@
MachineBasicBlock::iterator E) {
unsigned Time = 0;
for (; I != E; ++I) {
- if (!countsAsInstruction(*I))
+ if (I->isDebugValue())
continue;
if (I->isCall())
Time += 10;
@@ -848,12 +814,12 @@
assert(MBBI != MBBIE && "Reached BB end within common tail length!");
(void)MBBIE;
- if (!countsAsInstruction(*MBBI)) {
+ if (MBBI->isDebugValue()) {
++MBBI;
continue;
}
- while ((MBBICommon != MBBIECommon) && !countsAsInstruction(*MBBICommon))
+ while ((MBBICommon != MBBIECommon) && MBBICommon->isDebugValue())
++MBBICommon;
assert(MBBICommon != MBBIECommon &&
@@ -893,7 +859,7 @@
}
for (auto &MI : *MBB) {
- if (!countsAsInstruction(MI))
+ if (MI.isDebugValue())
continue;
DebugLoc DL = MI.getDebugLoc();
for (unsigned int i = 0 ; i < NextCommonInsts.size() ; i++) {
@@ -903,7 +869,7 @@
auto &Pos = NextCommonInsts[i];
assert(Pos != SameTails[i].getBlock()->end() &&
"Reached BB end within common tail");
- while (!countsAsInstruction(*Pos)) {
+ while (Pos->isDebugValue()) {
++Pos;
assert(Pos != SameTails[i].getBlock()->end() &&
"Reached BB end within common tail");